Stealth is a known term for low absorbability, or invisibility in the radar world and also invisibility to thermal imaging detection and observation, such as described, for example, in Eltics Ltd.'s U.S. Pat. Nos. 8,013,302 and 8,080,792, the disclosures of which are incorporated herein by reference in their entirety. These patents describe and claim an active adaptive stealth system made from active stealth plates that, inter alia, generate the same signature as the surroundings and blend into the background to become invisible to thermal cameras or thermal sights, for military purposes.
A disadvantage of the present system is that, although the plates become thermally equal to the background, any uncovered window panes remain with a significant signature—usually a negative signature from reflecting the cold sky. This signature does not match the background or the surroundings and, as such, the window can be detected by thermal sensors, such as thermal cameras and thermal sights. This, therefore, will decrease stealth performance of an asset (an object being protected) having uncovered windows.
An important factor is that the user of the assets wants to have a window to look out from, for the purpose of situation awareness of the battlefield, driving ability—with or without the aid of night vision goggles, known as NVG—and to reduce the claustrophobic psychological feel of the user.
Accordingly, there is a long felt need for a window for camouflaged assets, or any other portion of an asset that cannot be covered by plates, that can also be camouflaged, and it would be very desirable if such a stealth window could still be used for viewing through at the time it is camouflaged.